No more Mr Nice Guy

Since he became Mayor of London, the Tory maverick has shed his buffoon image and discovered a new dedication to work. The key, he tells Lynn Barber, is overcoming the need to be liked - and listening to Ken. So is Boris finally a safe pair of hands?

Five months into the job, Boris Johnson has already made his mark as Mayor of London by getting rid of the Metropolitan Police Commissioner, Sir Ian Blair. It is about time people started addressing him as Mr Mayor - he has earned it. But apparently nobody does - the young, eager-beaver staff at City Hall call him Boris, just as they called Ken Livingstone Ken. For such an incredibly important job, the mayoralty carries few if any trappings of power - no official car (Boris cycles to work), no official residence, no chain of office, no mayor's banquet, hardly even an expense account.

Boris of course is 'running late', so I chat to a nice young press officer about how City Hall has changed since Livingstone's day. 'It's more open,' he says. Apparently it used to be divided into cubicles, but one of Boris's first acts was to have all the partitions knocked down to make it open plan. His own office is still separate but, according to the press officer, Boris is very approachable. 'More so than Ken?' 'Probably, yes.'

Boris eventually emerges only 10 minutes late and greets me as an old friend, though I haven't seen him since I interviewed him five years ago. I was hopelessly charmed by him on that occasion - and then subsequently uncharmed when I read of his affair with Petronella Wyatt. This time, almost the first thing I see on entering his office is a copy of Woodrow (father of Petronella) Wyatt's Journals lying on the coffee table. Does Boris have some death-wish desire to remind me of the scandal?

The second thing I see is a man who looks exactly like Charles Moore, Boris's former editor at the Telegraph and predecessor at the Spectator, whom Boris introduces as his director of communications. Poor Charles Moore, I think, how embarrassing to work for a man who used to work for you. It is only when he speaks with a Welsh accent that I recognise him as Guto Hari, formerly of the BBC.

Meanwhile Boris is flinging open cupboards and showing me the famous wine collection he inherited from Livingstone's day. 'It took me about a month to find it because I didn't open any of the cupboards.' It looks very enticing, but Boris says it's too early to crack open. He is drinking again, though? (He gave up alcohol for the whole mayoral campaign.) 'Oh God, yes. I did find it one of the most tedious things I've ever done. The only thing was it did help me lose weight a bit, but I soon made it up again with eating. I think giving up alcohol is cruel, cruel, one of the cruellest and most deceitful things you can do to your body. I've taken more out of alcohol than alcohol has taken out of me. It's a great gift of the gods, in my view.'

Then it's over to the window to admire the view. 'Best view in London,' he says, 'absolutely fabulous, but you can't see it because you can't clean the windows. Well, you can, but it costs thousands of pounds, you have to get a cherrypicker. If you want to blame Norman Foster [who designed the building], do.' It is true that the windows are absolutely filthy - nevertheless it is still a great view, looking over Tower Bridge and the Tower of London.

Boris is still whirling about in a flurry of displacement activity, but eventually Guto Hari and I, acting as a pair of sheepdogs, herd him to the table. I tell him that when I interviewed him five years ago he was trying to have his cake and eat it, to be an MP and edit the Spectator at the same time. 'Well, I still am! Let's not beat around the bush here. My policy on cake is still pro having it and pro eating it!' But actually, although he still writes a weekly column for the Telegraph, he now seems to have committed himself wholeheartedly to politics.

He is, he says, thrilled to be mayor. 'It's the most wonderful job in British politics. Every day I wake up in a state of wonderment that I have been elected - obviously knowing that millions of other people wake up in a state of wonderment that I have been elected too! It is just brilliant fun, but also very hard. I realised that if you're going to make a difference you've got to work really flat out.' He works at least 12 hours a day, and says he has never worked harder in his life except for one period at Eton. 'When I was about 16 I worked ferociously hard for two terms and laid the foundations for all future activity - I thereafter never really did any academic work. But it's a bit like that now - I'm having to run pretty fast on my hamster wheel.' (Note the intellectual arrogance - two terms' work was enough to get him through A-levels and Oxford. According to his Oxford tutor, if he had done just a bit of work, he could easily have got a first. It didn't matter though - everyone accepts that he is brilliant.)

Many of his friends, he says, were surprised he even wanted to be Mayor of London. He had a comfortable seat as MP for Henley; he was earning reportedly £250,000 from the Telegraph as well as extras like £25,000 a show for Have I Got News For You. But his friends obviously underestimated his ambition. Has he lost any friends as a result?

'Yeah. It's true that there's a whole lot of people I might have hung out with or had lunch with that I haven't seen much of for the past five months and I do feel bad about that.' He thought he would miss the House of Commons but he doesn't at all. 'That's the most amazing thing about coming here, that not for one second have I thought, "Golly, I wish I was on my hind feet in the House of Commons" - no way! Better to reign in heaven than serve in hell or whatever the quote is.' ('Better to reign in hell than serve in heaven', actually - Satan in Paradise Lost

The first time he ever thought of being mayor was in about 1995 when he'd just come back from Brussels, where he was the Telegraph's EU correspondent, 'and I remember hearing someone on telly talking about having a Mayor of London and I thought "Wow, that would be a wonderful job!" And then, like so many things, it faded into the background. And then when Ken Livingstone was elected, like many people my age I was a bit of a Livingstone fan in those days. Obviously I particularly enjoyed it when he was sticking it so firmly up the Labour Party - I thought that was great.'

But about three years ago someone in the Tory party suggested he might stand as mayor, and 'my natural vanity and competitive spirit was piqued, but again I just filed it away as something I might do one day. But then I got increasingly interested in doing it, and finally decided to go for it. But I don't think you could say the Tory party was beating a path to my door! They were trying all sorts of other people - Greg Dyke, Brian Paddick - I was by no means their first choice. But having exhausted all other options, they then decided that they would put their shirt on me.'

At the time, I told him, I thought he was a sort of joke candidate.

'Did you really? That's both fascinating and insulting! But that was my own feeling of insecurity, because it was quite a thing to go up against Ken. In a way it was like Apocalypse Now - there was this deeply revered fellow, the Marlon Brando character who'd been a colonel and done incredible things at a fantastically young age, but then he'd gone up river and holed up in his lair and allowed things to go to his head. So I felt like Captain Willard, sailing up the long river. But I approached him with that sort of feeling of reverence, at the sad obligation of having to dispatch him.'

But he is still on surprisingly good terms with Livingstone and having dinner with him soon. Livingstone sometimes turns up at Mayor's Question Time, which Boris says is actually quite helpful, 'because this office has no constitutional opposition, so it's an important discipline to have someone who can say, "Well, I would do it this way." And Ken is public-spirited enough to want to do that. He does genuinely love London.'

Boris has definitely changed since his Spectator days. (Incidentally, he told me that, though he loved the Spectator, he thinks in retrospect he stayed there a year too long.) He said during the mayoral campaign that, in order for Londoners to take him seriously, he would have to learn to take himself more seriously, and he seems to have achieved it. He looks smarter for a start and uses less of the 'Cripes, Crikey' Just William mannerisms. I wondered if, at age 44, he was quite relieved to shed some of his buffoon image?

'Yes. The terrible truth, Lynn, is that the buffoon stuff clings to you like a burr and I'm afraid there's only so much auto-lobotomy I can do! The inner buffoon has a way of emerging! But I think the truth is that people did recognise that I was extremely serious about the mayoralty. At the end of a pretty exhausting nine-month campaign - it really went on and on and on - the proposition that I wasn't going to take it seriously was tested more or less to destruction.'

He has also managed to suppress some of his old desire to be liked and learnt to be more ruthless. 'You have to. And indeed you realise that there's a great selfishness in endlessly trying to be liked - it is terribly selfish. People elect you to do the tough things, because that's what you're there for. So yes. We had to reduce the London Development Agency considerably and lost about 93 people, and it's tough. And there will be things that I will have to do in the future which will also be tough. But to shirk them is selfish.'

Whether getting rid of Sir Ian Blair counted as tough is debatable, but it certainly marked a bold annexation of power. Simon Jenkins called it the moment when the mayoralty came of age. Actually, we can almost presage the change in Boris from his novel, Seventy Two Virgins, published in 2004. ('Ohmigod,' says Boris when I mention it, 'you've read my novel? That's the most exciting thing I've heard for weeks.') The protagonist, Roger Barlow, is an MP, older and less intelligent than Boris, but similar in many respects. He is coolly observed throughout the novel by his American research assistant, Cameron, who finds him puzzling. She admires him in some ways - 'He worked prodigiously hard. He got things done' - but she looks in vain for 'a knuckle of principle in the opaque minestrone of his views' and keeps wondering what, if any, are his ideals, his values, his core beliefs. He seems to say one thing to one person, the opposite to another; he also often spoils what should be a serious speech by putting in throwaway jokes. The Cameron commentary in the novel is tantamount to a critique of the old buffoon Boris by the new serious Boris, and perhaps an insight into the self-analysis that led him to change.

The novel also offers some insight into his views on women - always his weak point in my view. He has never been a friend to working women and there are plenty of digs at them in his columns. In the novel, Roger Barlow belatedly decides that he is going to work at his marriage. He makes a list of things he must do - pick up wet towels and put the electric toothbrush back on its stand; not fart under the duvet or leave half-eaten tins of tuna under the bed. Above all, he resolves, 'I'm going to start listening properly when she talks to me. I'm going to communicate. I'm going to stay awake after lights out, because it's always worth it in the end. I'm going to understand that the important thing is not to solve problems, but to discuss them. After 15 years, I'm going to get the point that marriage is not a final act; it's like a meeting of the European agricultural ministers, an endless negotiation of insolubles.' It doesn't sound too hopeful.

According to his biographer and friend, Andrew Gimson, Boris has had no end of affairs, not just the two with Petronella Wyatt and Anna Fazackerley that made it to the tabloids. Gimson takes the line that, of course, we can't expect politicians to live like monks, ho ho, but I feel this is never a great selling point with women voters. Given that everyone agrees that Boris's wife, Marina (daughter of the late Charles Wheeler), is just about the nicest woman in the world, and also given that Boris's mother was made so unhappy by his father's philandering that she had a long and serious nervous breakdown, you'd have thought Boris would have learnt to keep it in his trousers, or at least be very, very discreet. But, according to Gimson, he was always canoodling with women in the backs of taxis, and it was pure luck that no cabbie ever shopped him.

One of the great quotes in Gimson's book, though unfortunately unattributed, is: 'As well as being a philanderer, he's a great family man.' I can see it might be true in an odd way, and asked Boris if it was. This brought on one of his yelping, snorting, hair-rummaging routines to give him time to devise his answer and eventually it came: 'I took a sort of vow ages ago that when bowled any kind of ball like that, the great thing to do is to watch it very carefully for as long as possible as it flies through the air, and then you stick your bat straight out, put your foot forward, block it and retire into your crease. That's the only way to deal with that one.'

Right. So he doesn't want to take this opportunity to deny that he is a philanderer or to say that he is a reformed character? More yelps - and then the sturdy blocking of the ball. 'I'm not going to say anything except that I hugely admire the elegance with which you framed the question and the elaborate way that you dug the hole and placed the stakes at the bottom - but I'm not going to fall in!'

There is a hand-written placard behind his desk saying, 'Boris for PM', which he quickly explains was not his doing but given him by the trade union Unite. But is Prime Minister now in his sights? 'This is a very, very wonderful, very difficult, very absorbing job and I know how lucky I am to have got it, and the thing to do is work very, very hard at it, and in the immortal words of Michael Heseltine, I cannot foresee the circumstances in which I would go for anything else.' But of course circumstances can change and he is ambitious enough, and perhaps now serious and ruthless enough to go all the way. If only he can learn to be safe in taxis.

The gaffes and the glory - a life of Johnson

Born Alexander Boris de Pfeffel Johnson June 1964, in New York. The eldest of four children by former MEP Stanley Johnson and his first wife, painter Charlotte Fawcett. Father of four children with barrister Marina Wheeler, daughter of journalist Charles Wheeler, whom he married in 1993 after his first marriage to Allegra Mostyn Owen was dissolved.

Career1983-86 Studies classics at Balliol College, Oxford.1987 Starts at the Telegraph as a leader writer.1994-99 Assistant editor, Telegraph.1998 Makes first of several appearances on television's Have I Got News for You1999 Becomes editor of the Spectator2001 Elected MP for Henley-on-Thames.2005 Appointed Shadow Minister for Higher Education. 2008 Becomes Mayor of London.

He says:'Voting Tory will cause your wife to have bigger breasts and increase your chances of owning a BMW M3.'

Liverpool (2004)Incurs the wrath of many Liverpudlians with an article saying they 'wallow in a sense of vicarious victimhood'.

Adultery (2004)Claims the allegation of his four-year affair with Petronella Wyatt 'is complete balderdash. It is an inverted pyramid of piffle' and is promptly sacked from Michael Howard's frontbench team for lying.

Papua New Guinea (2006)Promises to 'add Papua New Guinea to my global itinerary of apology' after stating: 'For 10 years we in the Tory party have become used to Papua New Guinea-style orgies of cannibalism and chief-killing.'